1. Field of the Invention
The present invention relates to a leak detector for vacuum leak detection applications with a vacuum pump as well as the valves which control the leak detection process.
2. Description of the Related Art
The method of producing a differential pressure in the area of the chamber walls of a test object or similar, which is to be subjected to a leak test, is well known. A possibly existing leak is detected with the aid of a test gas which is present on the side having the higher pressure, and which, in case of a leak is then able to penetrate the chamber wall of the test object. The case of vacuum leak detection the differential pressure is produced by generating a partial vacuum on one side of the chamber wall of the test object. This may be implemented by connecting the test object itself to the vacuum pump and subjecting the outside to a test gas atmosphere, be it by spraying or generation of a test gas atmosphere within a test chamber. In a different approach, the object containing the test ,gas is placed in a test chamber, which is then evacuated.
Therefore, a suitable apparatus for vacuum leak detection is equipped with a vacuum pump which is employed for generation of the differential pressure. Frequently gas ballast pumps are used for this purpose. Leak detectors which are equipped with a mass spectrometer For detection of the test gas must be provided with an additional high vacuum pump to produce a pressure of approximately 10.sup.-4 mbar required for operation of the mass spectrometer.
Moreover, a leak detector for vacuum leak detection requires several valves to control the leak detection process. It is known to actuate these valves electromagnetically and to equip them with a closure spring, so that all valves are returned to their closed position in the event of a power failure. Valves of this type are large, complex and thus costly.